Mailbox support



FIG. 1 is a perspective view of my new ornamental design for a mailbox support;

FIG. 2 is a front view of the mailbox support shown in FIG. 1;

FIG. 3 is a right side view of the mailbox support shown in FIGS. 1 and 2;

FIG. 4 is a rear view of the mailbox support shown in FIGS. 1-3;

FIG. 5 is a top view of the mailbox support shown in FIGS. 1-4; and,

FIG. 6 is a bottom view of the mailbox support shown in FIGS. 1-5. 

The ornamental design for a mailbox support, as shown. 